Oily plugs/oily intake-m20 /// Update: Stuck valve? \\\

[Ether-D]

I just got a junkyard motor (1992 325ic) because it had a super clean head (in and out) and spankin new exhaust gaskets. This said to me that it had recent headwork and was a decent candidate for a replacement for my current DD with a random oil pressure issue and bad valve seals. And for $200 with a 5-speed attached, how could I go wrong?

So, I'm taking her apart because I have a bunch of replacement gasketry laying around and I want to know what the inside looks like.

The intakes of the new-looking head are very uniformly oily black, cooked-on black. The back sides of the intake valves are oily, the plugs are oily, and the head side of the intake runners are oily/black, but not the throttle body side of the intake. There is visible cross-hatching in the cylinders but also some uniform wear. I'm getting the feeling that the bottom of my "new" yard motor is shot.

Did I just buy a $200 head and 5-speed?

Thanks in advance.

[jlevie]

Two are two possibilities exist. The rings or cylinders are worn resulting in excessive blow by or there are intake leaks into the crank case resulting in higher flow through the breather hose.

[Ether-D]

The breather hose from the valve cover to the throttle body was nearly full of gunk. Maybe 1/2 restricted. It looked original. Does that narrow it down any?

[coldweatherblue]

doing a leakdown and smoke test would let you know what needs to be fixed.

I can tell you personally I was having the same problem and it ended up being a vacuum leak from the oil return tube intake o-ring.

[Ether-D]

That would be fantastic. Both o-rings were completely shot on that tube...

[jlevie]

A smoke test will tell if there are leaks anywhere.

[Kozworth]

I just got a junkyard motor (1992 325ic) because a random oil pressure issue and bad valve seals.

The back sides of the intake valves are oily, the plugs are oily, and the head side of the intake runners are oily/black, but not the throttle body side of the intake. There is visible cross-hatching in the cylinders but also some uniform wear.

Thanks in advance.

Yes, bad valve seals would be the cause of oily valves. Plugs would have to be a valve cover gasket, only thing above it to really leak down onto the plug holes.

I would guess a PCV issue with the oily intake runners.

What kind of wear really is in the cylinders? The m20s I've seen all had crosshatching, but didnt really seem to have any wear.

As for buying an engine with shotty oil pressure, I would have expected a whole bottom end refresh. Oil pressure is created by the clearances between the bearings, for example the main bearings and the crank. With excessive wear, the clearances are bigger thus reducing oil pressure. When I did rings, main/rod bearings, and rod bolts (tty bolts) it was 300 and some change, not including lower gasket set.

Honestly, you could probably sell the trans alone and make up for what you paid for the both. The heads go decently quick for the Eta guys, and worst case just throw a couple bucks to refresh the bottom end and youd be good.

[Ether-D]

Plugs would have to be a valve cover gasket, only thing above it to really leak down onto the plug holes.

I should clarify, it's the combustion side of the plug that is oily on the yard motor.

What kind of wear really is in the cylinders? The m20s I've seen all had crosshatching, but didnt really seem to have any wear.

I'll try to get a pic up...

for buying an engine with shotty oil pressure, I would have expected a whole bottom end refresh. Oil pressure is created by the clearances between the bearings, for example the main bearings and the crank. With excessive wear, the clearances are bigger thus reducing oil pressure. When I did rings, main/rod bearings, and rod bolts (tty bolts) it was 300 and some change, not including lower gasket set.

It was my current dd's motor that had the pressure issue. The yard motor may also, but I haven't run it yet.

Honestly, you could probably sell the trans alone and make up for what you paid for the both. The heads go decently quick for the Eta guys, and worst case just throw a couple bucks to refresh the bottom end and youd be good.

Right. Good point. Thanks for the answers folks.

[Kozworth]

If the electrode is oily, I would say it would probably be blowby past the rings hitting the spark plug during compression/exhaust stroke.

[Ether-D]

Huh???

Update.
I got the yard motor and tranny switched into my dd. I replaced front and rear seals, t-belt, water pump, oil pan gasket, valve cover gasket, head gasket and anything else that needed it.

Only a few hiccups.

I assumed the valves were adjusted on the new(ish) head and they were not. I took it out on it's first test drive and broke a rocker. I think because it was too loose and hammered itself to death. It was a little tappy on the test drive, then it was a lot tappy...

Limped it home, missing on at least the one cylinder, to find the broken intake valve on #3. I started looking closer to see what had to be done to fix it. The intake rocker shaft in the new AMC head (on the yard motor) appeared to have been beaten in with a sledge hammer. The front end was all flattened out like a tent spike. So I had to cut it into 7 pieces with my saws-all just to get it out. That was fun, not really.
Then I took all 6 rockers and rocker shaft from the knocking motor and got them successfully installed in the car. Adjusted all of the valves and when I got to the last intake valve, I noticed it was stuck open. Right, stuck open. I knew that if I rotated the motor by hand, the piston would eventually contact the valve and maybe close it. So I did, gently, and it worked. Then I rotated it again to see if it would get stuck again, and it did. WTfv¢k? At this time I'm looking at this thing, pissed, been messing with it all day, and now it's got a sticking valve. I look at the valve and convince myself it looks like it's angled to the left. So I then take a big flat screwdriver and pry it to the right a bit (I know this is probably horrifying Jlevie). Then I went back and rotated the engine by hand some more and it never got stuck again. Miracle? Dumb luck? Impending doom? Idk, but that shite is working for now and feels nice and strong.

Though I've got to be honest, I'm afraid to take it to redline cause I feel like that valve is gonna stick for a millisecond and turn my newly installed, nicely running motor to scrap. Opinions?

On a happy note the new transmission is quiet as can be and silky smooth. So I got that going for me, which is nice...

AND OMGOODNESS!!!!! KATE MIDDLETON IS IN LABOR!!!!!!!!!

[jlevie]

You have a bent valve (or possibly more). The head needs to come off, be torn down, and all of the valves checked.

[Ether-D]

Dammit, pretty sure I knew that was coming...

[Ether-D]

update...
The loud valve quieted down and I've been able to take her to redline a couple of times without incident. Hopefully it will hold out so I can build my 2.8... Fingers crossed.

[Ether-D]

Update:
Ok so I heard the unmistakeable snap-snap-snap of the valve sticking and getting smacked back down by the piston again. So instead of trying to save $70 by not pulling the head and replacing the gasket and bolts, I went ahead and swapped in my other head that I've been valve lapping and making perfect(ish). See, I had three old heads, all in various states of wellbeing. So I took all the best parts from all 3 heads and built the current one. All is completely well and real happy. She runs better than ever. Thanks again for your guidance.

edit: also, the head I pulled off (AMC, built by an asshole with a sledge hammer and a surplus of ignorance) with the sticky valve, well it only had single valve springs. No wonder I had a sticky one.

[Quinthirty]

I'm not sure where I read it, but it said something like some oil at the intake and throttle is acceptable. The question is, how much is "acceptable?"